Pageboys stand by as Queen Elizabeth takes her seat on the throne next to Prince Philip in the House of Lords to deliver the Queen's speech. Photograph: Alastair Grant/AFP/Getty Images

Whatever its content and however deadpan Her Majesty's inimitable delivery of it, every Queen's speech tells a slightly different political story. Wednesday's speech from the throne was no exception. This one said the coalition is losing its wider bearings and is becoming narrowly defined by events it cannot control.

That story was signalled right at the start. "My ministers' first priority will be to reduce the deficit and restore economic stability," the Queen announced. Nothing else she said yesterday really mattered. For the economy is not just her ministers' first priority now. It is their first and last and every priority in between. For this government, everything else is secondary.

This is very dangerous for any government, especially one rapidly losing a reputation for economic efficiency. The political problem of mankind, Keynes said, is to combine economic efficiency with social justice and individual liberty. The coalition risks being defined by economic inefficiency and social injustice. Once acquired, such reputations are hard to shake off.

This also reflects an important shift in the Conservative-Liberal Democrat coalition's animating purpose. Two years ago, the makers of the new coalition conceived an ambitious governing project that extended well beyond paying down the deficit. Optimists spoke of a larger liberal purpose to the Cameron-Clegg government – civil libertarian, internationalist, open-minded, communitarian, green and constitutionally modernising. Even sceptics could see that there was wider political ambition in the coalition agreement of 2010. But where is all that now?

True, some important vestiges of that bright, confident coalition morning still remain in the programme announced on Wednesday. The Green Investment Bank and House of Lords reform are both recognisably children of the 2010 agreement, though neither is much loved on the Conservative backbenches. The same goes for the reform of charity law, and parental leave rules. These are all progressive reforms.

But the coalition parties are increasingly at loggerheads. As a consequence the larger liberal conservative project that arguably framed the first year of the coalition is far harder to discern now. Indeed it would be difficult to say that the coalition now has any distinct project beyond economic stability and the government's survival. Not that these are unimportant. But all the coalition's eggs are suddenly in this one frayed basket – a far cry from the earlier strong sense that it had a vision of the kind of Britain it sought to build.

To some extent this narrowing of purpose has been difficult to avoid. The government is operating in exceptionally difficult financial and economic circumstances. A combination of the eurozone crisis and global recession has undoubtedly accelerated the usual process of midterm unpopularity.

Inevitably they have beaten some of the innocence and ambition out of ministers here, as in many other countries – and perhaps, eventually, in France too.

But coalition ministers are not simply the victims of events. They are also authors of some of their misfortunes. The self-inflicted wounds of the March budget showed the same casual political recklessness that had marked the student finance and health service policies. The major unforced budget errors have done significant reputational damage. Far more important, they have also pushed the coalition off the centre ground, making Labour more attractive to swing voters. Foolishly, the government has been forced to circle its wagons around its highly challengeable claim to superior economic competence.

That is the reason why a lacklustre Queen's speech matters so much. It tells a story of political uncertainty that ought to seriously worry coalition strategists. It is one thing to renew your coalition and redefine yourself as strong on the economy if that's palpably what you are. It is quite another to do so when that claim is looking increasingly vulnerable, and in fragile economic circumstances in which incumbents in most countries seem so vulnerable at the ballot box. This is a moment when the government needs to have something clearer and more uplifting to say. Wednesday's speech squandered that opportunity, but it did so because the coalition parties now struggle to agree on the country they want to build.

Tough economic times inevitably reduce a government's options. But the coalition could have and should have used the Queen's speech to assert a clearer set of social values, perhaps on care of the elderly, or perhaps on energy prices, or even – though it goes against the grain to do it – on social housing. Any of these might have reasserted the coalition's claims to be a truly national government, concerned with social justice as well as economic rectitude.

A Queen's speech will occasionally be a statement of earth-shaking legislative activity across every department of government. Treat yourself to a read of Labour's King's speech of August 1945 for an example of that approach – nationalisation of the mines, introduction of a health service, freedom for India and the establishing of the United Nations all in one legislative programme. But it does not always need to be on that epochal level.

What a Queen's speech always needs to do, however, is send an overarching message to the nation about what the government is for. Tony Blair never forgot that obligation, though he undoubtedly also overdid the lawmaking. But Blair never failed to use the Queen's speech to set an agenda. If Cameron was more creative he might have done this on Wednesday. The opening debate of the session ought to be a state-of-the-nation moment, a chance for the prime minister to require the nation's attention for a speech that justifies the government's priorities for the year ahead.

Cameron has been facing a big political task this spring. He needed to recreate his connection with mainstream voters. He needed to show doubters he really is, as he used to claim, a different kind of Conservative. He needed to make the case that his government has a bigger vision than simply cutting public spending. Not for the first time, Lord Ashcroft got it right this week when he observed that the government needs a sense of direction not a change of direction. None of this is going well. If Cameron is not very careful, his own and his party's fortunes may be going decisively into reverse.